But their analysis goes much farther back than just three years. Among other things, they found that rising temperatures, declining snowpack, and decreasing precipitation in autumn and spring have acted to extend California’s fire season in the shoulder seasons. They also determined that climate change has already doubled the frequency of extreme fire weather days since the 1980s (see the illustration at the top of the article).

The research also found a long-term trend toward more extreme fire weather conditions occurring in both southern and northern California at the same time.